Item 21 - Water Supply Assessment for the Warner - Red Hill Mixed Use Development Project

Home Browse Search

T HE W ARNER P ROJECT W ATER S UPPLY A SSESSMENT A UGUST 21, 2020 F USCOE E NGINEERING , I NC. 20 4. R EGIONAL W ATER S UPPLY R ELIABILITY The City of Santa Ana currently depends on Metropolitan and local groundwater resources to provide the majority of its water supply. This section provides a description of the ability of Metropolitan, OCWD and the City to ensure that adequate water supplies will be available to satisfy the City’s growing water demands including the proposed Project through 2040 during normal, single dry year and multiply dry year scenarios. 4.1 METROPOLITAN WATER DISTRICT REGIONAL WATER SUPPLY RELIABILITY Metropolitan’s 2015 Urban Water Management Plan (UWMP) was finalized in June 2016 and has been prepared in compliance with Water Code Sections 10608.36 of SB X7-7 and Sections 10610 through 10656 of the Urban Water Management Planning Act (Act). The information included in the 2015 UWMP represents the most current and available planning projections of supply capability and demand developed through a collaborative process with the member agencies, including the City of Santa Ana. The Act requires reporting agencies to describe their water reliability under a single dry-year, multiple dry-year, and average year conditions, with projected information in five-year increments for 20 years. Metropolitan updates its retail municipal and industrial (M&I) projection periodically based on the release of official regional demographic and economic projections. The projections of retail M&I water demands used in the 2015 UWMP are based on data from the Southern California Association of Governments (SCAG) 2012 Regional Transportation Plan/Sustainable Community Strategy (April 2012) and the San Diego Association of Governments (SANDAG) Series 13: 2050 Regional Growth Forecast (October 2013). The projected regional water demand is adjusted to account for water conserved by Best Management Practices from active, code-based, and price-effect conservation. Supply analysis includes Colorado River supplies, SWP supplies and existing and proposed storage programs through Metropolitan’s service area. Colorado River Aqueduct (CRA) supplies include supplies that would result from existing and committed programs and from implementation of the Quantification Settlement Agreement (QSA) and related agreements. State Water Project (SWP) supplies are estimated using the 2015 SWP Delivery Capability Report distributed by DWR in July 2015. In regard to storage, Metropolitan assumed 2015 storage levels at the start of simulation and used the median storage levels going into each of the five- year increments based on the balances of supplies and demands. See Table 8 below showing Metropolitan’s ability to meet growing demands in normal, single-dry and multiple-dry year climate scenarios.